The present invention relates to:
(i) an ultrasonic processing device (for instance, an ultrasonic cleaning device, a resist-stripping device) used in a process for fabricating electronic parts of, for example, flat displays such as a liquid crystal display element, a PDP (plasma display panel), and an EL (electro-luminescent) panel, sensor elements of plane- or line-scanning types such as an image sensor, semiconductors such as LSI, solar butteries, and printed-circuit substrates; and
(ii) a method for fabricating electronic parts, using the foregoing device.
The present invention particularly relates to an ultrasonic processing device that can be adapted as an ultrasonic cleaning device and as a resist-stripping device effective for processing a large-size substrate with a width of several hundreds millimeters or over, as well as to a method for fabricating electronic parts using the foregoing device.
Conventionally, in fabrication of electronic parts of flat displays such as a liquid crystal display element, a PDP (plasma display panel), and an EL (electro-luminescent) panel, sensor elements of plane- or line-scanning types such as an image sensor, and semiconductors, a cleaning process for removing particles, soils, and the like adhering to substrates, etc. is indispensable.
Further, in fabrication of such electronic parts, a photolithography process with use of resist is repeatedly applied so as to form predetermined patterns on a substrate. Since the resist need be removed from the substrate upon completion of the photolithography process, the resist-stripping process is indispensable in fabrication of electronic parts in many cases.
Therefore, to efficiently execute the foregoing cleaning process and the resist removing process, cleaning devices or resist-stripping devices of various arrangements have been used conventionally. As the cleaning device or the resist-stripping device, an ultrasonic processing device is often used, since the foregoing cleaning process and the resist-stripping process, in particular, become more efficient if they are executed with projection of ultrasonic.
For instance, a first example of the same is a batch-type ultrasonic processing device (ultrasonic cleaning device). A cleaning section provided in an ultrasonic processing device of this type is arranged so as to be equipped with, as shown in FIG. 35, an ultrasonic oscillation element (vibrating element) 103 such as a vibrating plate (diaphragm), at a bottom of a cleaning bath 101 reservoiring cleaning liquid (liquid). In the cleaning section, flow 102 is formed in the cleaning liquid while a processing object such as a substrate 110 is dipped in the cleaning liquid, and in this state the ultrasonic oscillation element 103 is caused to generate ultrasonic. This causes ultrasonic to be projected to the cleaning liquid, then to the processing object via the cleaning liquid, thereby causing the processing object to be cleaned. Incidentally, in FIG. 35, the device is drawn in a simplified manner for conveniences"" sake, and a concrete arrangement for forming the flow 102 of the cleaning liquid in the cleaning bath 101 is omitted.
Next, a second example of the ultrasonic processing device is a nozzle-type ultrasonic processing device in which processing liquid (liquid) to which ultrasonic is projected is supplied through a nozzle to a processing object. A processing section provided in the ultrasonic processing device of this type is equipped with an ultrasonic processing nozzle 111 disposed above a substrate 110 as a processing object, as shown in FIG. 36. Besides, the ultrasonic processing nozzle 111 has a nozzle opening 112 in a slit form that is provided along a width direction substantially orthogonal to a transport direction of the substrate 110.
In the nozzle-type arrangement, the substrate 110 as the processing object is transported in the predetermined transport direction (indicated by an arrow A in the figure) while it is horizontally held. To an upper surface of the substrate 110 being transported, processing liquid (pure water, for instance, is used as cleaning liquid) 107 to which ultrasonic is projected (applied) by the ultrasonic oscillation element 103 is jetted through the nozzle opening 112 of the ultrasonic processing nozzle 111.
In other words, in the foregoing ultrasonic processing device of the nozzle type, processing liquid to which ultrasonic is projected is jetted through the ultrasonic processing nozzle 111 provided in the width direction, over the entire width-direction dimension of the processing object that is traveling. As a result, as the processing object is traveling, the whole surface of the processing object is subjected to the ultrasonic processing (for instance, cleaning). This, in the case of cleaning for instance, enables to efficiently remove fine particles (particles), soils or the like, made of an organic material and a metal, that adhere to the substrate 110, while in the case of resist stripping, this enables to efficiently remove resist.
Furthermore, a third example of the ultrasonic processing device is a wet processing device disclosed by the Japanese Publication for Laid-Open Patent Application No. 177978/1998 (Tokukaihei 10-177978 [Date of Publication: Jun. 30, 1998). As shown in FIG. 37, this wet processing device is provided with (i) an introduction path 122 having an inlet 121 at one end thereof for supplying wet processing liquid 117, (ii) a discharge path 124 having an outlet 123 at one end thereof for discharging wet processing liquid 117a having been used for wet processing, out of the wet processing system, and (iii) an opening section 126 that is opened toward a processing object such as a substrate 110, at an intersection 125 where the introduction path 122 and the discharge path 124 cross so that the other end of the introduction path 122 and the other end of the discharge path 124 meet each other.
The foregoing introduction path 122 inclines so that the inlet 121 side part is disposed upper than the intersection 125 side part, while the discharge path 124 likewise inclines so that the outlet 123 side part is disposed upper than the intersection 125 side part. The wet processing liquid 117 is introduced by the inclining introduction path 122 and supplied via the opening section 126 to the substrate 110 that travels in the arrow A direction in the figure, so that a desired wet processing operation is performed. The wet processing liquid 117a having been used in the processing operation is discharged out of the wet processing system through the discharge path 124.
In the wet processing device arranged as above, ultrasonic may be projected during the wet processing operation. For instance, as shown in FIGS. 38(a) and 38(b), a singularity of an ultrasonic oscillation element 103 may be provided above the intersection 125. Alternatively, as shown in FIG. 39, a plurality (three in the figure) of ultrasonic oscillation elements 103 may be linearly arranged in a width direction of the processing object (horizontal direction) above the intersection 125. Alternatively, as shown in FIGS. 40(a) and 40(b), a plurality (three in the figures) of ultrasonic oscillation elements 103 may be linearly arrayed in a transport direction of the processing object (in this case, in a lengthwise direction of the processing object). By so doing, projection of ultrasonic is enabled. (In FIGS. 38(b), 39, and 40(b) the position of the ultrasonic element(s) 103 falls on the position of the intersection 125, but the reference numeral thereof is omitted for conveniences"" sake.)
The foregoing wet processing device, since being arranged as above, exhibits a higher processing capability than conventionally, while a quantity of the wet processing liquid 117 used can be decreased by not less than one tenth. Moreover, in the case where the ultrasonic oscillation element(s) 103 is (are) provided as described above, a processing object is subjected to projection of ultrasonic as well as the wet processing operation, whereby the processing capability is enhanced.
Furthermore, a fourth example of the ultrasonic processing device is an ultrasonic processing device disclosed in the Japanese Publication for Laid-Open Patent Application No. 106998 (Tokukaihei 10-106998 [Date of Publication: Apr. 24, 1998]). As shown in FIG. 41, this ultrasonic processing device, aimed for applying a predetermined processing operation to a substrate 230 such as a liquid-crystal-use glass substrate as a processing object with use of lower surface processing liquid L1 and upper surface processing liquid L2, is arranged to include: a transport system 231 for transporting the substrate 230 in a predetermined direction by means of a plurality of rollers that support the substrate 230 from its lower surface; an oscillation container 232 that opens upward and to whose inside the lower surface processing liquid L1 is supplied; an ultrasonic vibrator 233 that is provided at the bottom of the oscillation container 232 and that applies ultrasonic vibration to the lower surface processing liquid L1 supplied to the inside of the oscillation container 232 by means of a vibrating plate 233a; an ultrasonic oscillator including an electric circuit connected with the ultrasonic vibrator 233; and a plurality of nozzles 234 that are provided above the substrate 230 and that supply the upper surface processing liquid L2 with respect to the upper surface of the substrate 230. Incidentally, the foregoing ultrasonic vibrator 233 and the vibrating plate 233a compose a vibrating element section (vibrating element) for applying ultrasonic vibration with respect to the lower surface processing liquid L1.
In the foregoing ultrasonic processing device of the fourth example, the ultrasonic processing operation with respect to the substrate 230 is performed as follows: (1) the substrate 230 is transported in a manner such that the lower surface thereof is brought into contact with the lower surface processing liquid L1 that is pushed up to above a level surface of the liquid in the oscillation container 232 by ultrasonic vibration applied thereto by the vibrating plate 233a; and (2) the upper surface processing liquid L2 is supplied from two positions so that the two streams collide at an area of the upper surface of the substrate 230, opposite to the area of the lower surface of the substrate 230 in contact with the lower surface processing liquid L1.
Incidentally, the recent tendency of the manufacture of electronic parts of semiconductor devices, liquid crystal display (LCD) elements, etc. is such that a large number of electronic parts are simultaneously fabricated for enhancement of productivity. Further, in the case of LCD elements in particular, larger-size base substrates from which electronic parts are produced are used, since LCD elements with large-size screens (for instance, those with diagonals of not less than 20 to 30 inches) are demanded.
The following is a concrete example of an LCD element. In the case of a TFT (thin film transistor)xe2x80x94type LCD element, when industrial mass production was substantially started, a size of a base substrate was more or less 300 mmxc3x97400 mm. Recently, however, the size of a base substrate is not less than several hundreds millimeters square, and those nearly 1 meter long in the lengthwise direction has become subjected to mass production.
Furthermore, from the viewpoint of enhancement of productivity of the foregoing electronic parts, the fabrication of electronic parts is preferably performed as incessantly as possible. For instance, it is not preferable that the fabrication process includes a process in which electronic parts are left to stand for a certain period, since it lowers productivity.
The ultrasonic processing devices or wet processing device of the foregoing first through fourth examples raise a problem that they cannot to fully meet requirements for such enhancement of productivity in the production of electronic parts.
First of all, in the case of the batch-type ultrasonic processing device of the first example, the processing object (substrate 110 shown in FIG. 35) has to be left to stand for a certain period during the ultrasonic processing operation. Therefore, the lowering of productivity in the production of electronic parts could possibly be caused. Furthermore, the ultrasonic processing device of this type requires volumes of processing liquid, and moreover, in the cleaning case, the processing operation tend to become non-uniform, since the processing liquid could be retained or the flow velocity could vary unless the flow 102 of the processing liquid (cleaning liquid) in the processing bath is sufficiently controlled.
Furthermore, to compensate the lowering of productivity, in using the foregoing batch-type ultrasonic processing device, usually a plurality of processing objects (electronic parts) are simultaneously processed, as shown in FIG. 35 (in FIG. 35, a plurality of substrates 110 are provided in the cleaning bath 101, with the lengthwise direction of the substrate 110 matched to the vertical direction). This simultaneous processing however tends to cause higher frequency of such processing liquid retention as well as an increase in variation of the flow velocity. Besides, in the cleaning case, the processing liquid reservoired in the processing bath is normally recycled through filters or the like and re-used, and replaced after a certain period elapsed, but the cleaning operations tend to vary as time passes, due to degradation of quality of the processing liquid.
Furthermore, in the case where a plurality of processing objects are simultaneously processed, or in the case where a larger-size processing object is processed, the foregoing processing bath (cleaning bath 101 in FIG. 35) need be in a larger size. This means that the entirety of the ultrasonic processing device need be in a larger size.
Next, in the nozzle-type ultrasonic processing device of the second example, in the case where the processing object is a large-size substrate 110, it is necessary to employ a singularity of a large and long ultrasonic oscillation element 113 in the ultrasonic processing nozzle 111, in place of the ultrasonic oscillation element 103 that is normally used, as shown in FIG. 42. This is for projection of ultrasonic over the entire width-direction dimension of a processing object. Such a large and long ultrasonic oscillation element 113, however, has a problem of insufficient reliability.
More specifically, since the foregoing ultrasonic oscillation elements 103 and 113 are made of ceramic, produced by baking, production of an ultrasonic oscillation element long in length such as the ultrasonic oscillation element 113 necessarily undergo the following drawbacks: (1) it is difficult to produce the elements in uniform sizes; (2) it is less resistible against local cracks due to stress caused by heating or the like, thereby having low reliability; (3) ultrasonic output is uneven inside the ultrasonic oscillation element 113; and (4) as to a plurality of ultrasonic oscillation elements 113, they have great differences between their ultrasonic outputs.
In other words, in the case of nozzle-type ultrasonic processing devices, they cost high since it is difficult to manufacture the ultrasonic oscillation elements 113 as a key of the processing operation in stable qualities. Besides, margins need be added to the period required for manufacture of the ultrasonic oscillation element 113, causing the manufacture period to be prolonged, thereby resulting in that it is not suitable for practical application.
Then, applied to the foregoing nozzle-type ultrasonic processing device is a technique of employing the ultrasonic oscillation element 103, which is a standard product, or a quasi-standard product, which is easily available, and which is highly reliable. In this technique, a plurality of the ultrasonic oscillation elements 103 are arrayed in series as shown in FIG. 43 over the width-direction dimension of the processing object, so as to form an element array 104. By so doing, it is theoretically possible to project ultrasonic over the entire width-direction dimension of the substrate 110 from the ultrasonic processing nozzle 111, in the case where the processing object is a large-size substrate 110 as above.
Actually, however, the foregoing technique of forming the element array 104 leads to a problem that uniform ultrasonic processing operations cannot be performed.
Even though the ultrasonic oscillation elements 103 are produced in the same manner, their ultrasonic outputs more or less vary from one another, and in forming the element array 104, a circuit for correcting the output variation is required in each of the ultrasonic oscillation elements 103. Therefore, in forming the element array 104, insulating regions (herein synonymous with element spaces) 114 in a predetermined width each must be formed between the ultrasonic oscillation elements 103.
Actual spaces as the insulating regions 114 depend on the type and size of the ultrasonic oscillation elements 103, but in the case where oscillation elements W-357LS-380 each equipped with a vibrating plate of 100 mmxc3x9715 mm in size (available from Honda Electronics Co., Ltd.) are used, spaces of at least about 0.2 mm each are formed as the insulating regions 114.
By forming the insulating regions 114, the ultrasonic oscillation elements 103 are insulated from each other, thereby causing variation of the outputs to be surely corrected, and in addition, suppressing an undesired interference effect of ultrasonic generated by adjacent ultrasonic oscillation elements 103.
At portions of the processing object corresponding to the foregoing insulating regions 114, however, ultrasonic is not sufficiently projected. Therefore, even if conditions such as the frequency of the ultrasonic, the output of the ultrasonic, and the flow rate of the processing liquid are optimized to some extent and the ultrasonic projection is carried out during a certain period, the foregoing portions corresponding to the insulating regions 114 cannot obtain the same effects of the ultrasonic projection as those at the other portions. Such non-uniformity in the processing operation causes a longer processing period to be required, or causes variation in processing periods thereby making efficient processing of an entire surface of the processing object difficult, as well as other problems.
Furthermore, the aforementioned value of about 0.2 mm as the space functioning as the insulating region (element space) 114 is a minimum requisite value that allows the region to exhibit effects such as suppression of the interference effect of ultrasonic and insulation, and a greater space is preferably provided so as to more efficiently avoid the interference effect and the like. Setting the space for the insulating region 114 greater, however, leads to a problem that the processing operation become further less uniform. Incidentally, the minimum requisite space (at, for instance, a value of about 0.2 mm) is hereinafter referred to as interference avoidance space.
The following description will explain how the processing operation becomes non-uniform. For instance, a substrate 110 to which not less than several hundreds of foreign substances (particles) or soils 100 adhere, as shown in FIG. 44, is subjected to a cleaning operation by means of an ultrasonic cleaning device adapting the foregoing technique that uses the foregoing element array 104, for a certain period (for instance, for a time of t). As a result, as shown in FIG. 45(a), the foreign substances or soils 100 remain at portions of the substrate 110 corresponding to the insulating regions 114 (indicated by two-dot chain lines in the figure).
On the other hand, in the case where the processing operation is continued for more than the foregoing period (for instance, for not less than a time of 2 t, which is twice the time of t), substantially all the foregoing substances or soils 100 are removed as shown in FIG. 45(b). However, it also results in an increase in the cleaning operation time, wasteful use of the cleaning liquid, and wasteful use of electric power by the device. Furthermore, an increase in the spaces for the insulating regions 114 could possibly make it difficult to eliminate non-uniformity of the cleaning operation, even with much time spent for the cleaning operation.
In the case where an adhesive force of the foreign substances or soils 100 is weak, or in the case where the foreign substances or soils 100 are few in number as shown in FIG. 46, however, it is possible to clean the same at a sufficient probability as shown in FIGS. 47(a) and 47(b), by means of the foregoing device, if it is used as a finishing cleaning bath. Incidentally, FIG. 47(a) illustrates a result of a cleaning operation carried out for a time of t, while FIG. 47(b) illustrates a result of a cleaning operation carried out for a time of not less than 2 t.
Furthermore, identical problems arise in the case of a resist-stripping device. For instance, as shown in FIG. 48, resist (photoresist) 115 for formation of patterns by photolithography is laminated in a film form (indicated by hatching in the figure) on a surface of the substrate 110. After the photolithography process, a resist-stripping operation is carried out for a certain period (for instance, for a time of t) by means of a resist-stripping device adapting the foregoing technique for forming the element array 104. As a result, as shown in FIG. 49(a), most of the resist can be stripped, but the resist remains in a line form at portions of the substrate 110 corresponding to the insulating regions 114.
To investigate the cause, strengths of ultrasonic were measured at a center of the ultrasonic oscillation element 103 and at the foregoing insulating region 114. As a result, it was discovered that the strength of ultrasonic lowers at the insulating region 114 to about 50% to 60% of that at the center of the ultrasonic oscillation element 103 (in-plane strength distribution occurs). This is because the element array 104 vibration does not show in-plane uniformity.
Furthermore, even in the case where the resist-stripping operation is continued for a period twice the normal period (for a time of not less than 2 t) like the case of the ultrasonic cleaning device, the resist cannot be completely removed, remaining at portions corresponding to the insulating regions 114, as shown in FIG. 49(b). Moreover, in the case where the output is forcibly increased so as to surely strip the resist from an entirety of the surface of the substrate 110, there is a possibility that characteristics of TFT elements and the like provided on the substrate 110 could shift, or such elements could be damaged.
Incidentally, the foregoing substrate 110 has a substrate size of, for instance, 360 mmxc3x97465 mm, and is provided with fine patterns in the xcexcm order on its surface, but the patterns are omitted in the figures since it is impossible to illustrate such fine patterns. Further, it was discovered that, in the case where a process for stripping the resist by ultrasonic processing is applied after the resist is laminated on the entire surface of the substrate 110 as described above, uniformity of the ultrasonic projection ability of the ultrasonic processing device can be evaluated.
Furthermore, the foregoing ultrasonic oscillation element 103 is damaged or broken during a short period due to heat generated, unless it is operated in liquid without bubbles or the like. Therefore, during the ultrasonic oscillation, surroundings of the ultrasonic oscillation element 103 need be filled with liquid such as the processing liquid 107.
The above-described nozzle-type ultrasonic processing device, however, has a nozzle opening 112 facing downwards above the substrate 110 as the processing object, and is arranged so that the processing liquid 107 is jetted downwards through the nozzle opening 112 (see FIG. 36). Therefore, bubbles tend to intrude through the nozzle opening 112. Furthermore, a distribution path of the processing liquid 107 (more specifically, an ultrasonic processing nozzle 111, a cleaning-liquid-supply pipe, a cleaning-liquid-supply pump, etc.) extends downwards or diagonally downwards, and bubbles generated upon operation of the ultrasonic oscillation element 103 provided in the distribution path (more specifically, inside the ultrasonic processing nozzle 111) tend to remain therearound. Moreover, the bubbles having intruded therein are hardly discharged to outside the distribution path of the processing liquid 107.
Therefore, to flow the processing liquid 107 without stagnation so as to prevent bubbles from remaining around the ultrasonic oscillation element 103, a complex structure is required, which is, for instance, characterized as follows: (1) a plurality of processing liquid supply paths are provided inside the ultrasonic processing nozzle 111; and (2) the inside wall of the ultrasonic processing nozzle 111 is formed in a tapered shape. Besides, to discharge bubbles through the nozzle opening 112, it is necessary to flow a great quantity of the processing liquid 107 at all times, with the opening area of the nozzle opening 112 and the like taken into consideration. These problems have become severer as the substrate 110 processed becomes larger in size.
In the case of the foregoing wet processing device of the third example also, there arise identical problems to those of the nozzle-type device of the second example. Namely, it becomes difficult to adapt a longer ultrasonic oscillation element 113 suitable for a processing object that becomes in a larger size. On the other hand, in the case where an ultrasonic oscillation element 103 of a normal size is used, the processing operation becomes non-uniform, with resultant effects at portions corresponding to the insulating regions 114 differing from those of the other portions.
Finally, in the case of the ultrasonic processing device of the fourth example, it is difficult to push up the lower surface processing liquid L1 uniformly to a large-size processing object such as a long substrate, and therefore, it is difficult to apply a uniform processing operation with respect to the foregoing processing object. Furthermore, since it is arranged so that the lower surface processing liquid L1 supplied from the bottom of the oscillation container 232 is discharged over the upper edges of the oscillation container 232, the flow velocity of the lower surface processing liquid L1 that is brought into contact with the substrate 230 is lower. Therefore, the processing operation of spraying the upper surface processing liquid L2 in a shower form over an upper surface of the substrate 230 provides high effects, while the processing operation with respect to the lower surface of the substrate 230 provides effects relatively low. As a result, there arise, for example, the following problems: (1) the upper surface processing liquid supplied to the upper surface of the substrate 230 goes round to the lower surface, thereby causing foreign substances to adhere to the lower surface again; and (2) since the simultaneous processing with respect to the both surfaces is not highly effective, inversion processing of the substrate 230, for example, is required. Furthermore, like in the cases of the second and third examples, it becomes difficult to adapt a longer ultrasonic oscillation element suitable for a processing object (equivalent to the substrate 230) that becomes in a larger size. On the other hand, in the case where an ultrasonic oscillation element (here, equivalent to a vibrating plate 233a disposed inside the oscillation container 232) of a normal size is used, the processing operation becomes non-uniform, with resultant effects at portions corresponding to the insulating regions between the ultrasonic oscillation elements differing from those of the other portions.
The present invention was made to solve the aforementioned problems, and an object of the present invention is to provide an ultrasonic processing device that is capable of effectively carrying out a cleaning operation, a resist-stripping operation, etc. by projecting ultrasonic uniformly over an entirety of the a large region by means of vibrating elements each having a size smaller than a region to be subjected to ultrasonic, as well as to provide an electronic parts fabrication method using the foregoing device.
To achieve the foregoing object, an ultrasonic processing device in accordance with the present invention is an ultrasonic processing device for applying an ultrasonic processing operation to a processing object, the device is arranged so as to include (1) plurality of vibrating elements for generating ultrasonic, and (2) means for moving the processing object in a predetermined direction relatively with respect to the vibrating elements, and the device is further arranged so that (i) regions to which the vibrating elements project ultrasonic are ultrasonic-projected regions each having a predetermined width in a width direction that is substantially orthogonal to the predetermined direction, and a whole arrangement of the plurality of vibrating elements planarly extend in the predetermined direction and in the width direction, and that (ii) by moving the processing object relatively in the predetermined direction, ultrasonic-projected regions of the vibrating elements are caused to cover an ultrasonic processing target region of the processing object, so that ultrasonic should be projected to a complete entirety of the ultrasonic processing target region.
For instance, in the case where a width of an ultrasonic-projected region by each vibrating element (equivalent to the foregoing predetermined width) is smaller than a width of the ultrasonic processing target region of the processing object, ultrasonic projection to an entirety of the ultrasonic processing target region was conventionally impossible without a vibrating element as long as or longer than the width of the ultrasonic processing target region.
However, according to the foregoing arrangement, a plurality of vibrating elements are arranged so as to planarly extend in the predetermined direction and the width direction both, as well as so that, when the respective ultrasonic-projected regions by the vibrating elements fall on the ultrasonic processing target region, the foregoing ultrasonic processing target region is completely (non-defectively) covered with the ultrasonic-projected regions, resulting in that ultrasonic is projected throughout the entirety of the ultrasonic processing target region non-defectively. Therefore, uniform projection of ultrasonic to a large region is ensured with use of vibrating elements that are easy to get and have high reliability, standard products or quasi-standard products.
Therefore, a uniform ultrasonic processing operation with respect to an entirety of a surface of a large-size processing object can be realized, and ultrasonic processing operations can be uniformly applied to a plurality of processing objects under the same conditions. Consequently, it is possible to realize a uniform ultrasonic processing operation of high performance. Besides, since the processing time can be shortened, processing costs can be reduced.
Therefore, this enables uniform ultrasonic projection to a large-area region by means of a combination of a plurality of vibrating elements that are easy to get and have high reliability such as standard products or quasi-standard products, not requiring preparation of a long vibrating element.
Incidentally, needless to say, xe2x80x9cultrasonic-projected regions of the vibrating elements are caused to overlap each other on an ultrasonic processing target regionxe2x80x9d may indicate that xe2x80x9cthe ultrasonic-projected regions are caused to partly overlap each other so as to completely cover the ultrasonic processing target region.
Furthermore, to achieve the aforementioned object, an electronic parts fabrication method in accordance with the present invention is an electronic parts fabrication method including the ultrasonic processing step for applying an ultrasonic processing operation to a processing object, and the method is arranged so that (i) in the ultrasonic processing step, a plurality of vibrating elements for generating ultrasonic are used, and that (ii) the ultrasonic processing step includes the sub-step of moving the processing object in a predetermined direction relatively with respect to the vibrating elements, so that ultrasonic-projected regions of the vibrating elements should be caused to partly overlap each other on an ultrasonic processing target region of the processing object, in order to cause ultrasonic to be projected to a complete entirety of the ultrasonic processing target region.
According to the foregoing method, the vibrating elements are arranged so that their ultrasonic-projected regions partly overlap each other so as to completely cover the entirety of the foregoing ultrasonic-processing region, resulting in that ultrasonic is projected throughout the entirety of the ultrasonic processing target region non-defectively. Therefore, uniform projection of ultrasonic to a large region is ensured with use of vibrating elements that are easy to get and have high reliability, standard products or quasi-standard products. Besides, since the processing time can be shortened, processing costs can be reduced.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.